Stress urinary incontinence is an involuntary loss of urine on a sudden rise in the abdominal pressure as in coughing, sneezing or lifting weight. This happens when the urethra closes incompletely due to intrinsic deficiency of the muscles of urethra or hyper mobility of the urethra. Normal urethral muscle function and the normal anatomical contour of the urethra are altered due to over stretching of pelvic organs during vaginal deliveries. Obesity also brings about similar changes in the urethra. Diabetes causes deterioration of nerves and muscles of urethra. Chronic cough due to smoking or other lung conditions is also a risk factor in causing stress incontinence of urine. Stress urinary incontinence varies in the degree of loss of control. It may consist of occasional leakage of a few drops of urine or it may amount to severe loss of urine needing several diapers a day. Most of the time, it interferes in the normal social life of the persons. In severe cases it becomes a big expense for diapers.
Stress urinary incontinence is rare in men. Most commonly it is due to injury to the muscles and the nerves of urethra that may occur in radical prostatectomy for the cancer of the prostate.
The treatment of stress urinary incontinence can be tried with non-surgical methods. This consists of developing strength in the muscles of urethral sphincter by Kegel exercises. Dr. Arnold Kegel, a gynecologist, has popularized exercises that he designed to strengthen the pelvic floor muscles that work on the urethra. These exercises could be helpful in early cases or could strengthen the muscles before the symptoms develop. A vaginal pessary, which consists of a stiff ring, can be placed in the vagina to press against the urethra to prevent leakage until the bladder contracts to expel the urine. A pessary is often not easy for the patient to insert or remove. As a result, a physician usually inserts the pessary into the patient. In Addition, a pessary can induce vaginal infection.
Surgical treatment is the mainstay in stress incontinence of urine. In some cases walls of the urethra can be approximated by injecting contigen via a cystoscope. Contigen is like a thick gel and it is made from bovine tissue. It acts like a bulking agent to approximate the walls of the urethra. However, because it is a foreign material, patient has to undergo allergy test for it. After it is injected, contigen has the tendency to gradually leak out and the injection has to be repeated. Besides contigen, some other bulking materials are also available. However, these bulking agents are successful in very few cases.
The main aim in all surgical procedures for stress urinary incontinence is to give support under the urethra against which the urethra is compressed when abdominal pressure suddenly rises as in coughing, sneezing or lifting heavy objects. Several operations have been in vogue over the time. In Marshall Marchetti Krantz urethropexy and in Birch urethropexy, the procedures are carried out through an abdominal approach. These procedures are more invasive and have longer recovery time. Laparoscopic approach through the abdomen has also decreased in popularity.
The most commonly performed procedures for stress urinary incontinence are the sling procedures. These procedures have some variations, but all are comparatively minimally invasive surgeries. They all are based on using a sling under the urethra to compress it so that leakage of the urine is prevented during a sudden rise in the abdominal, and consequently the bladder, pressure during coughing, sneezing or lifting heavy objects. While this condition is not fatal, the inconvenience and the lack of freedom for women to control the urge to urinate affect a woman's lifestyle. There are variations in the sling material such as autologous rectus fascia, porcine skin, homologous fascia, and synthetic sling. There are some variations in the approaches to sling placement. The sling can be placed through supra-pubic approach, vaginal approach, or an obturator approach. As discussed earlier, the most common method for the treatment of female urinary incontinence is to suspend the urethra using an implantable sling. In the past, slings have been supported in different ways in the abdominal region. Most common of these methods is to support the urethra include suspending form the pubic bone.
Benderer et. al in U.S. Pat. No. 5,836,314 discloses a procedure for treating female stress incontinence. In his method, Benderer suggests the use of suspension sutures to sling the urethra and one or more bone anchors in the pubic bone to suspend the sutures.
Most of the traditional surgical methods for implantable and non-implantable devices are very complicated and cumbersome to use. Any surgical intervention, especially in the pelvic region, is very complicated, requiring long recovery and ambulation.
Bouttier in U.S. Pat. No. 7,229,404 B2 describes a device for suspending the urethra using a sling and anchors.
Smith et. al. in U.S. Pat. No. 7,261,723 B1 describes a device sling apparatus that is delivered using a needle handle from below the urethra. The device is also suspended from above to provide the compression on the bladder neck.
Johan et. al in U.S. Pat. No. 7,083,568 describes a sling wherein the sling apparatus can be permanently changed during and or after implantation.
Pretorius et. al. in U.S. Pat. No. 6,786,861 B1 describes a method by which a distensible member is inserted dorsally between the urethra and the pubic bone. By inflating the distensible member via a valve, the distensible member constricts the urethra.
In almost all cases, slings made from a biocompatible material, such as polypropylene, have been used to suspend the bladder neck. Various means to suspend the sling have also been disclosed by many inventors.
Invariably, the sling is hung from either the abdominal wall or from the pelvic bone. Various attachment methods also have been disclosed. In spite of the many inventions, and the devices that materialized subsequently, female stress incontinence is still essentially unresolved, proving that a simple solution to this annoying problem is still needed. In light of the fact that the physiology of the ailment changes post operatively, it is essential that one would consider a device that can adjust the degree to which the urethra is pinched post operatively, and after few weeks or months.
The present invention discloses such methods wherein the device can be adjusted either by a ratcheting mechanism or by inflating balloon that in turn tugs on the sling, compressing or decompressing the bladder neck and/or a combination of the ratchet mechanism and balloon inflation. It is preferred to use a non-distensible balloon for this purpose rather than distensible balloon, as distensible balloons will have a tendency to push the inflating mediums due to the elastomeric forces associated with them.
The major problem with all the previous sling procedures is that there is no control on the amount of tension they place on the urethra. The surgeon only guesses the amount of tension he should leave in the sling. During surgery, the patient is usually under general anesthesia. The body is completely relaxed. Therefore, during the operation, the tension on the sling is different than when the patient is no longer under anesthesia. Also, during surgery, the patient is lying down, and the position of the bladder and the urethra is different to when the patient is standing up and in walking state. In the first few days after surgery, there is some edema and swelling due to the surgical trauma. The tension of the sling is comparatively higher during this period, and the sling may get too loose after the swelling subsides. Once the sling is placed and the surgery is completed, there is no way to alter the tension on the sling. Because of these reasons, there is a considerable failure rate in these types of surgeries. As one would expect, there are some cases where the sling is too loose and the surgery has not succeeded in alleviating the urinary stress incontinence. In other cases, the sling is too tight and the patient cannot urinate. The patient would need catheterization to empty the bladder until another surgery is performed to loosen the sling.
The amount of the pressure exerted by the sling on the urethra can be a significant issue. If the degree of pressure is low, the incontinence is not cured. On the other hand, if the pressure is high, the urethra would not allow urine pass on active voluntary contraction of the bladder. This delicate balance in the degree of compression needed to achieve normal urination cannot be achieved through guessing or trial and error. Presently, none of the procedures for the treatment of stress urinary incontinence have any control on the degree of compression placed on the urethra. The novel device presented here is the only device where the compression placed on the urethra is adjustable.
In addition, clinical evidence has shown that the current procedure to cause complications of infection resulting in osteitis. The suspension of the sling on the pubic bone with metallic or non-metallic screws, and similar fasteners, has resulted in other complications, as the screws are not very stable, and can even detach from the bone. As such, one aspect of the present invention recommends that the sling be hung and supported in the periostium of the pubic bone ramus.